1. Field of the Invention
This invention relates to a solenoid valve with enhanced sealing and opening characteristics. More particularly, it relates to such a valve that will utilize any inlet or outlet leakage pressure to provide a better outlet or inlet seal in a bi-directional manner. Most especially, it relates to such a valve suitable for controlling flows in gas chromatographs and similar precision applications.
2. Description of the Prior Art
A variety of solenoid valve configurations for controlling fluid flow are known in the art. Representative prior art solenoid valve designs are disclosed in the following issued U.S. Pat Nos.: 3,878,859, issued April 22, 1975 to Grob et al. and 4,453,700, issued June 12, 1984 to Otsuki et al. Other examples of prior art solenoid valves suitable for gas chromatograph and similar applications are commercially available from Pyronetics Division of Parker-Hannifin and from ITT under the designation of Microsol.
Prior art solenoid valve designs provide a single seal between their fluid inlet and outlet. If this single seal becomes ineffective, fluid flow between the inlet and outlet is allowed to take place. Prior art solenoid valves which allow interchanging of the inlet and outlet connections are not symmetrical in configuration and therefore do not operate in a symmetrical manner. Many prior art solenoid valve designs either will not open or will stick open under certain operating conditions.